Below is a link showing how to build a pepper mill around the shiftless Crush Grind. In order to fill the mill, you have to include a plug in the top. The only design I've seen that really leveraged the shaftless mechanism was a mill that looked like a pear and the stem was removable and that's how it was filled. Other than that, I'm not sure what the shaftless design buys you. Also, with the shaftless mechanism, it looks like you need to be extremely accurate with your dimensions. With the shafted Crush Grind mechanism, you can still make the mill whatever size you want and just cut the shaft to the length you need. I cut them to length and re-taper the end slightly in a pencil sharpener.
I bought a shaftless Crush Grind mechanism with my last order, but I've yet to build anything with it.